|First image of Mercury ever taken from a |
spacecraft in orbit around Mercury. Sent from Messenger,
which reached orbit around Mercury on March 17. Photo
sent on March 29, 2011
Photo credit: NASA
MESSENGER will be in a highly elliptical orbit around Mercury, coming as close as 200 km to the surface or being as far away as 15,000 km.
The rayed crater in this image is the impact crater Debussy. It is a central-peak crater with rays that extend hundreds of kilometers across the planet. This crater is visible in Earth-based radar images of mercury because of the prominent bright rays. The name honors the famous French composer, Claude Debussy (1862-1918).
Mercury, Venus, Earth and Mars are the rocky planets of our solar system. Mercury is "extreme": the smallest, and the densest (after correcting for self-compression). It has the oldest surface, and may have incipient, though not well-developed, plate tectonic features. It has the most extreme variations in daily surface temperature.
MESSENGER scientists are focusing on six questions: (1) Why is Mercury so dense? (2) What is the geologic history? (3) What is the nature of its magnetic field? (4) What is the structure of its core? (5) What are the unusual materials at the poles (which are permanently shadowed)? (6) What volatiles are important at Mercury?
The MESSENGER website is here.